Carbohydrate/ˌkɑːrbəʊˈhaɪdreɪt/ Definition 1 of 2Pro Tip 1/3Dietary Importance Carbohydrate is key in discussions about nutrition and diet. Dietitians say that carbohydrates should be included in every meal. Pro Tip 2/3Energy Source Often mentioned as a primary source of energy for physical activities. Athletes consume a lot of carbohydrates before a competition. Pro Tip 3/3Weight Discussions Carbohydrates are frequently mentioned in conversations about weight gain or loss. Low-carbohydrate diets are popular for weight loss.